In dissociative disorders, one aspect of a person’s psychological
makeup
is dissociated (separated)
from others. A commonality among most
people diagnosed with these disorders is their susceptibility to trance
states, hypnosis, and
suggestibility. Hans Eysenck's research suggests as well that
these are more likely to be nervous extraverts.

Dissocative amnesia is the “inability to recall
important
personal
information, usually of a traumatic or stressful nature,” (DSM
IV) but
more than what we would characterize as ordinary forgetfulness.
It is not
due,
of course, to a physical trauma, drug use, or a medical
condition. Instead, it is due to the ability that these people
have to focus away from certain memories that disturb them.

It has been increasingly common for people to report having
forgotten
childhood traumas, especially sexual abuse, while in the care of
certain
therapists. Recent researchers now believe that the “recovered
memories”
that
these patients report are actually implanted in the minds of these very
suggestable people by their over-enthusiastic therapists. It is
still
not known whether all recovered memories should be suspect or not,
although
memory research suggests that trauma is more typically remembered well,
not poorly.

Fugue is amnesia accompanied by sudden travel away from a
person’s
usual haunts. Time away can range from a few hours to
months.
When these people return to normal, they often don’t remember what
happened
while they were away. A few adopt an entirely new identity while
“on the
road.”

Dissociative identity disorder -- formerly known as multiple
personality
-- involves someone developing two or more seperate
“identities”
that take over the person’s behavior from time to time. The
"usual" personality doesn't remember what happens when an alternate
personality takes over. Dissociative identity disorder is not the
same
as schizophrenia, but does have some similarities. In
schizophrenia, voices and impulses are seen as coming from
outside oneself, while in dissociative identity disorder, they are seen
as coming from within, in the form of these alternate personalities.

One of the first cases to reach the public was the story of Eve
White. Eve White (a pseudonym, of course), was a mild mannered
woman with a domineering husband. She found herself waking up
with garish makeup, hangovers, and other signs that she had been out
carousing during the night. This alternate personality that took
over occasionally was called Eve Black. Eventually, the two
personalities were brought together, and Eve's story was made into a
movie with actress Joanne Woodward called "The Three Faces of
Eve." A
second movie was much more popular: "Sybil." This was the
true story of a woman who had been severely abused by her schizophrenic
mother, and developed (supposedly) 26 personalities.

People with multiple
personalities are usually easily hypnotized, making it likely that this
disorder may be caused or at least aggravated by therapists,
intentionally or unintentionally,
much like recovered memories. It is looked upon with skepticism
by
many psychologists.

On the other hand, it may also be understood as a modern version of
a fairly common occurance in the nonwestern, premodern world:
Spirit possession. In cultures where the powers of gods, ghosts,
and demons are taken for granted, people sometimes feel possessed by
these outside personalities. In more modern societies, lacking
the possession explanation, people assume that the alternate
personality is internal.

Depersonalization is the “persistent or recurrent feeling of
being detached from one’s mental processes or body....” (DSM
IV) Often the world seems
odd as well, which is called derealization.
Physical
objects
may seem distorted and other people may seem mechanical. Again,
these
people may be particularly easy to hypnotize, and the feeling can be
induced
even in normal people under hypnosis. Half of all adults may have
experienced a brief episode of depersonalization or derealization in
their
lifetime, but it is most common in people who have suffered from abuse,
the loss of a loved one, or have seen combat. It is also common
under the influence of hallucinogens like
LSD.

Dissociative trance disorder
is an unofficial category often referred to by psychologists and
psychiatrists working in premodern, nonwestern societies. Trance
is a narrowing of one's attention so that some things (such as sight,
movement, or even outer reality) are placed outside awareness.
Cross-cultural therapist Richard Castillo, in his book Culture and Mental Illness, says
that trance is "an
adaptation with great individual and species survival value." It
is not far from such non-pathological states as hypnosis and meditation.

Castillo gives numerous examples:

Amok is found in Malaysia
and Indonesia. The word comes from the Sanskrit for "no
freedom." It involves a person losing their sense of self,
grabbing a weapon such as a machete, and running through the village
slashing at people. Afterwards, they have no memory of what they
have done and are typically excused from any damage, even if their
actions resulted in someone's death!

Grisi siknis is found among
teenage girls and yound women of the Miskito indians in
Nicaragua. They also run wild with machetes, occasionally
assaulting
people or mutilating themselves. They have no memory of their
actions.

Pibloktoq or arctic hysteria
is found among polar eskimos. For anywhere from a few minutes to
an hour, a person takes off their clothing and runs screaming through
the snow and ice, as a response to a sudden fright.

"Falling out" (in the
Bahamas) involves falling to the ground, apparently comatose, but
hearing and understanding what is going on around you.

"Indisposition" (in Haiti)
is a possession trance understood as a response to fear.

"Fits" (in India) is a
seizure-like response by some women to family stress, curable by
exorcism or by simply telling her husband to protect her from her
inlaws!

In the west, these kinds of behaviors are often classified as impulse control disorders, along
with trichotillomania, compulsive gambling, pyromania, and kleptomania
(discussed with anxiety disorders).
One of these - intermittent explosive
disorder - is
basically the same as running amok, and is commonly known as "going postal."